the rough/square-edged side. If a snap ring is positioned such that its flat side is pressed into the rounded edge of the groove then when load or force is applied, the flat edge of the snap ring will "bite" into the rounded edge of the retaining groove. The snap ring will distort and ride up the rounded edge, spreading an external snap ring and compressing an internal snap ring. This leaves the clip prone to being forced out of its groove and failing at its retaining function. The accompanying images illustrate the correct orientation of the snap ring in its groove. Wet or dry lubrication is recommended to reduce friction against the circlip and maintain function. References External links Definition with picture Historical background Fasteners